The Los Angeles flood of 1938 was one of the largest floods in the history of Los Angeles, Orange, and Riverside Counties in southern California. The flood was caused by two Pacific storms that swept across the Los Angeles Basin in February-March 1938 and generated almost one year's worth of precipitation in just a few days. Between 113–115 people were killed by the flooding. The Los Angeles, San Gabriel, and Santa Ana Rivers burst their banks, inundating much of the coastal plain, the San Fernando and San Gabriel Valleys, and the Inland Empire. Flood control structures spared parts of Los Angeles County from destruction, while Orange and Riverside Counties experienced more damage. The flood of 1938 is considered a 50-year flood. It caused $78 million of damage ($ in dollars), making it one of the costliest natural disasters in Los Angeles' history. In response to the floods, the U.S. Army Corps of Engineers and other agencies began to channelize local streams in concrete, and built many new flood control dams and debris basins. These works have been instrumental in protecting Southern California from subsequent flooding events, such as in 1969 and 2005, which both had a larger volume than the 1938 flood. Background Due to its location between the Pacific Ocean and the high San Gabriel Mountains, the Los Angeles Basin is subject to flash floods caused by heavy orographic precipitation from Pacific storms hitting the mountains. Due to the arid climate, soils are too hard to absorb water quickly during storm events, resulting in large amounts of surface runoff. The steep, rocky terrain of the San Gabriel Mountains further contributes to the rapid runoff and resultant flooding hazard. Between February 27 and 28, 1938, a storm from the Pacific Ocean moved inland into the Los Angeles Basin, running eastward into the San Gabriel Mountains. The area received almost constant rain totaling from February 27-March 1. This caused minor flooding that affected only a few buildings in isolated canyons and some low-lying areas along rivers. Fifteen hours later on March 1, at approximately 8:45 PM, a second storm hit the area, creating gale-force winds along the coast and pouring down even more rain. The storm brought rainfall totals to in the lowlands and upwards of in the mountains. When the storm ended on March 3, the resulting damage was horrific. Effects The 1938 flood destroyed 5,601 homes and businesses and